The invention relates to a comminution apparatus that is suitable to be operated in conjunction with a material cooler for cooling cement clinker and other materials.
The present comminution apparatus is utilized in a cooling apparatus of the general class for cooling particulate material (e.g., cement clinker or other mineral materials), which has been burnt in a kiln or heated by some other process. Such apparatus can comprise traveling grate coolers, thrust grate coolers, G Coolers and the like. The method of operation of the above and other coolers is well known in the art. For example, in reciprocating grate coolers, the hot particulate material discharged from the kiln outlet typically undergoes quenching in the material inlet part of the cooling apparatus and is then moved, distributed as well as possible, to consecutive rows of grates on which additional cooling is then carried out while the material to be cooled is transported along a path extending from the material inlet to the material outlet of the cooler on said grates. Typically, the cooling air which is blown through the hot material in the recuperation zone of the cooling apparatus is then reused or recycled further generally as air for combustion in the preceding kiln.
In reciprocating grate coolers, grates for cooling or combustion are generally equipped with overlapping rows of grate plates, of which some are mounted in a fixed position and others are reciprocating, which generally means that they oscillate in a longitudinal direction, with the forward stroke of the reciprocation being the direction in which the particulate material to be cooled travels through the cooler, and they thereby serve in part to facilitate the movement of the material through the cooler. The grate plates are mounted on a carrier beam which is transverse to the direction of material flow through the cooler, with adjoining grate plates abutting. The air needed for cooling or combustion is introduced from below the grate plates through port like openings to enter, penetrate and pass through the bed of material to be cooled or burned, with said material lying on top of the grate plate.
Typical clinker coolers are comprised of one or more (typically up to as many as four) drive sections. Each drive section will move, in a reciprocating manner, as an assembly of grate plates. Typically, such an assembly of grate plates will be comprised of from about 15 to about 45 rows of grate plates, with each row being comprised of 6 to 18 individual grates.
Roll breakers have been used in conjunction with such clinker cooler installations for more than a decade. The main purpose of this equipment is to maintain a majority of the clinker particles, which of course are unevenly sized, that pass through at least a portion of a cooling apparatus below a specified diameter, which typically is 25 mm or less, because there is better heat transfer between cooling air and small clinker particles. Typically, a roll breaker will contain at least two rolls in series, and generally between two to six rolls, with each roller assembly being supported by a frame and with all the rolls being of the same size and on a fixed center line. The rolls are contained within a common frame.
In one example of prior art, Great Britain patent application 2,016,952A teaches a roll breaker that has at least two crushing rolls located at the end of a cooling grate underneath a screen assembly with there being a further roll crusher with at least two crushing rolls provided downstream of the screen assembly. Another type of roll breaker known in the art contains, in addition to crushing rolls, one or more so-called transport rolls, which transport rolls rotate in the same direction and serve to deliver the larger pieces of material to at least one pair of crushing rolls. The crushing rolls rotate in opposite directions to each other to thereby draw the material into the gap located between the crushing rolls, whereupon the material will be broken down into smaller pieces. This gap between crushing rolls is set at a certain desired dimension to provide clinker particles having an optimum size for heat transfer. However, the crushing rolls are of course subject to extreme wear and, with extended use, the gap between the crushing rolls will increase and the resulting size of the crushed particles will become larger than the desired optimum size, thereby reducing the efficiency of the heat transfer process of the cooler. When such prior art roll breakers become worn, it has been typical for the user to elect to run the crushers with such a wider gap, which obviously impacts on the efficiency of the cooler. Otherwise, the cooler must be shut down for a lengthy period of time in order to replace any worn rolls or worn segments on each roller, at a considerable cost.
In addition, many prior art roll breakers of the type described are not particularly effective in transporting material into the gap between the crushing rolls, thus causing a back up of material and thus reducing the efficiency of both the roll breaker and the cooling apparatus.
It would be advantageous, therefore, to have a roll breaker in which the gap between the rolls can, such as at times when the rolls begin to exhibit wear, be adjusted in a comparatively fast, efficient and inexpensive manner. In addition, it would be advantageous to provide for a roll breaker which has a more efficient material transport and crushing mechanism.